Bluetooth is among the most widely accepted ways for two devices to communicate with each other. Every phone, tablet, and laptop comes with Bluetooth built in, as do several peripherals. So with a little do-it-yourself (DIY) tinkering, you can do some wonderful things with this technology.

Naturally, you’ll need two Arduino boards and two Bluetooth receiver modules for this. To begin, start with his basic tutorial where he teaches you how to remote control an LED light on the slave Arduino via the master Arduino.

Then move on to the more advanced project, where the slave gauges the temperature outside and sends the signal to the master inside, which in turn displays the reading on a screen.

This might be the easiest and most useful project to start with. With an Arduino board, a few wires, and an LCD screen, you can type text on your phone and display it on the screen. Just like that, you’ll have a wireless notice board.

You’ll need a mini Bluetooth receiver, adapters for a DC jack and a 2.5mm to 3.5mm jack, and that pair of old headphones. You’ll also need a soldering iron and a multimeter, both of which you can find at any hackerspace.

In the project, you will be taking apart the headphones and the receiver, and then soldering them together. Then you fit everything into the speaker, make a hole for the 3.5mm jack and the charging cable.

Unlike a car, there is no stereo for your two-wheeler. But hey, Patrick Panikulam has figured out a way to upgrade a motorcycle helmet by adding Bluetooth speakers inside it.

You’ll need old headphones and a Bluetooth receiver module to take apart, a 3.5mm audio male pin, and some thin flat wires. And of course, a full-face helmet. It’s actually a pretty easy hack to put together, with minimal soldering and some make-do adjustments like sticking the speakers with double-sided tape.

But while this adds some much-needed features, remember, safety first. Don’t text and drive, don’t turn up the volume such that you can’t hear others, and generally do everything you can to keep your attention on the road.

For this project, you’ll need a custom PCB designed by the maker. You can order it directly from EasyEDA or download the bill of materials and schematics to make your own. It’s probably wiser to order it.

Wouldn’t it be cool if you could open a lock with your phone? The Bluetooth padlock is awesome, but it is also the most advanced project in this list. It requires some special equipment like a milling machine, a 3D printer, a laser cutter, and other things that you will find in your school or a local hackerspace.

Don’t be intimidated though. The maker, Kirand1, has written a clear set of instructions that take you through the steps of creating a housing, the shackle and locking pin, the faceplace, and then inserting the electronics (based on an Arduino board).

The final version will let you lock and unlock the padlock with the tap of a button on an app. It even works on a smartwatch.